Abstract: In order to improve the performance of sizing nozzles,MgO stabilized zirconia sizing nozzle material was prepared using ZrO₂ fine powder(d₅₀=3,5 and 8 μm) as the raw material,polyvinyl alcohol aqueous solution as the binder,extra adding different mass fractions (2.0%,2.5%,2.8%,3.0% and 3.5%) of MgO,and heat treating at 1 700 ℃ for 2 h.The effects of the MgO addition on the phase composition,microstructure and properties were studied.The bulk density,the cold compressive strength and the strength retention ratio after 3 cycles of thermal shock of the samples increase first and then decrease with the increase of the MgO addition.When the MgO addition is 2.5%,the comprehensive performance of the sample is the best with 0.75% apparent porosity,5.51 g·cm^-3 bulk density,980 MPa cold compressive strength,and 1 025 MPa cold compressive strength after three thermal shocks.

Key words: zirconia, magnesia, density, thermal shock resistance

摘要： 为提高定径水口的性能,以ZrO₂细粉(d₅₀分别为3、5、8 μm)为原料,以聚乙烯醇水溶液为结合剂,外加不同质量分数(分别为2.0%、2.5%、2.8%、3.0%、3.5%)的MgO,于1 700 ℃保温2 h热处理后制备了氧化镁稳定氧化锆质定径水口材料,探究MgO添加量对其物相组成、显微结构及性能的影响。研究表明:随着MgO添加量的增加,试样的体积密度、常温耐压强度和热震三次后强度保持率均先增加后减小;MgO添加量为2.5%(w)时,试样综合性能最优,显气孔率为0.75%,体积密度为5.51 g·cm^-3,常温耐压强度为980 MPa,热震3次后的常温耐压强度为1 025 MPa。

关键词: 氧化锆, 氧化镁, 致密度, 抗热震性